Relationship of the lungs to the left atrium of particular relevance for ablation of atrial fibrillation.

BACKGROUND: Symptoms of possible lung and pleural injury such as chest pain and hemoptysis occur during and after radiofrequency ablation (RFA) and cryoablation (CA) of the left atrium (LA) for treatment of atrial fibrillation (AF). We determined the anatomical relationship of the lungs to the LA with particular reference to areas commonly targeted during AF ablation.
METHODS: Distances from the LA endocardium to the lungs were measured from pre-procedure CT angiograms of 100 consecutive patients (71 males, age 60 ± 8 years) who underwent AF ablation.
RESULTS: In 97% of the patients, the posterior right pulmonary vein antrum was <5 mm from the lower lobe of the right lung (RLL) over a supero-inferior distance of 3.6 ± 1.5 cm (minimum distance 1.2 ± 0.7 mm). The right inferior pulmonary vein (RIPV) ostium was <5 mm from the RLL in 94% (mean 2.7 ± 1.9 mm). The right superior pulmonary vein ostium was <5 mm from the RLL in 29% (mean 7.1 ± 3.8 mm). The medial segment of the right middle lobe was <5 mm from the carina between right pulmonary veins in 83% (mean 3.6 ± 1.9 mm). The mitral isthmus was <5 mm from the lingula in 5% (mean 9.4 ± 3.6 mm). The inferior lobe of the left lung was <5 mm from the posterior aspect of the ostia of the left inferior and superior pulmonary veins in 9 and 0%, respectively. The bronchi were <5 mm from the LA in 5%.
CONCLUSIONS: The lungs are intimately related to sites of the LA commonly targeted during AF RFA. Whether this anatomical proximity translates into clinically significant potential for collateral lung damage during RFA merits further study.